Safety and Effectiveness of the Alma System in Treating Primary Postpartum Hemorrhage

Inclusion Criteria: 1. Adult Female, 18 years of age or older at time of consent. 2. Subject or her legally authorized representative is able to understand and provide consent to participate in the clinical investigation. 3. Subjects who present with an atonic uterus for at least 10 minutes after expulsion of placement with failure to obtain contraction and/or Subjects who have lost blood post-partum \> = 500 ml and according to the Investigator's judgment, require an intervention. 4. Failed first-line intervention of uterotonics and uterine massage/bimanual uterine massage to stop bleeding. Exclusion Criteria: 1. Subjects who do not provide informed consent to participate in the clinical investigation. 2. Subjects who deliver at a uterus size \< 34 weeks. 3. Subjects who have lost greater than 1000 ml of blood. 4. Subjects who have abnormal PT, PTT and INR 5. Subjects who present with retained placenta, uterine lacerations, or for any other conditions outside of atonic post-partum hemorrhage. 6. PPH that the investigator determines to require more aggressive treatment, including any of the following: * Hysterectomy; * B-lynch suture; * Uterine artery embolization or ligation; * Hypogastric ligation. * Known uterine anomaly. * Ongoing intrauterine pregnancy. 7. Placental abnormality including any of the following: * Known placenta accreta; * Retained placenta with known risk factors for placenta accreta (e.g., history of prior uterine surgery, including prior c-section and placenta previa); * Retained placenta without easy manual removal. 8. Known uterine rupture. 9. Unresolved uterine inversion.